Wisdom teeth appear as the last tooth in the mouth and begin to erupt around the age of 16 years. Wisdom teeth are removed primarily to eliminate the potential for infection & damage to adjacent teeth. The jaws of most individuals are not large enough to accommodate the wisdom teeth and they remain either under the gum tissue & often become partially exposed where they have a greater potential for becoming infected.
When the dentist determines that no room exists for the wisdom teeth to erupt into normal position, then they must be removed. When a wisdom tooth is blocked from erupting, it is termed impacted. Most dentists and patients agree that is favorable to have one surgery & have them removed in one visit.

Once discomfort, swelling, food impaction & symptoms of pocketing begin, removal is the most prudent course since these symptoms will not go away but, increase in severity.